This invention relates primarily to a car power source battery apparatus used as a power source for a motor that drives an automobile, such as a hybrid car or electric automobile.
A car power source battery apparatus used as a power source for an automobile driving motor connects many batteries in series to increase output voltage. This is for the purpose of increasing output of the driving motor. In a battery apparatus used for this type of application, a large number of batteries are housed within the apparatus to produce a large output voltage. This type of battery apparatus is cited, for example, in Japanese Patent Application Disclosure HEI 10-270006 (1998). As shown in the exploded oblique view of FIG. 1, the power source apparatus cited in this disclosure is provided with a holder case 52 which houses battery modules in a plurality of rows. The holder case 52 is formed from plastic in the shape of a rectangular box with an open top. Circular openings 53a are provided in both end planes 53 of the holder case 52 for insertion of long narrow, circular cylindrical battery modules. Further, to hold and stabilize battery modules, intermediate planes 54 are provided parallel to the end planes 53, and circular openings 54a are also established in those intermediate planes 54. Battery modules are inserted through the openings 53a in the end planes 53 and through the openings 54a in the intermediate planes 54 to retain the battery modules in specified positions in the holder case 52.
Since a large number of battery modules are Inserted through openings and held in a holder case of this configuration, it has the drawback that the apparatus is difficult to manufacture and cost of manufacture is high. This is because openings for insertion and retention of battery modules are formed in both end planes and Intermediate planes. Molding a holder case provided with openings In both end planes and intermediate planes requires a mold with a complex structure. This is because regions, which form openings in both end planes and intermediate planes, cannot be easily removed from the mold.
Further, in a holder case of this configuration, it is necessary to form the openings provided in both end planes and intermediate planes exactly the same shape as the external shape of the battery modules. This is because battery modules cannot be retained without gaps if the openings are larger than the battery modules, and battery modules cannot be inserted in the openings if they are smaller than the battery modules. The problem is that it is difficult to manufacture battery modules having an extremely precise outside diameter. There is some degree of error in the outside diameter of circular cylindrical batteries manufactured in quantity, Consequently, even if openings in both end planes and intermediate planes are accurately formed, it is difficult to insert, without forming gaps, and firmly retain all battery modules in those openings. This is because the outside diameters of the battery modules are different.
To hold battery modules, which have outside diameter variation, openings must be formed with a size that allows insertion of battery modules having the largest outside diameter. Therefore, when a battery module having a slightly small outside diameter is inserted through the openings, gaps are formed between the battery module and the openings. If gaps are formed, the apparatus has the drawback that both end planes and intermediate planes cannot stably retain the battery module without movement.
Still a further problem with a holder case, which has openings the same size as battery module outside diameter, is the extreme amount of trouble required to insert and set the battery modules. This is because snug insertion of battery modules through small openings without forming gaps cannot be performed in a smooth fashion. Therefore, insertion of a large number of battery modules to assemble a holder case is extremely labor intensive, and assembly cost becomes high. This has the drawback that, in combination with the high cost of holder case manufacture, the total cost of the battery apparatus becomes remarkably high.
A holder case with the structure shown In FIG. 2 was developed with the object of eliminating these drawbacks (Japanese Patent Application Disclosure 2000-223096, (2000)).